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53e1b683 | 1 | /* SPDX-License-Identifier: LGPL-2.1+ */ |
758dd67e LP |
2 | /*** |
3 | This file is part of systemd. | |
4 | ||
5 | Copyright 2010 Lennart Poettering | |
6 | Copyright 2014 Michal Schmidt | |
758dd67e LP |
7 | ***/ |
8 | ||
dccca82b LP |
9 | #include <string.h> |
10 | ||
758dd67e | 11 | #include "hash-funcs.h" |
46e16b34 | 12 | #include "path-util.h" |
758dd67e LP |
13 | |
14 | void string_hash_func(const void *p, struct siphash *state) { | |
15 | siphash24_compress(p, strlen(p) + 1, state); | |
16 | } | |
17 | ||
18 | int string_compare_func(const void *a, const void *b) { | |
19 | return strcmp(a, b); | |
20 | } | |
21 | ||
22 | const struct hash_ops string_hash_ops = { | |
23 | .hash = string_hash_func, | |
24 | .compare = string_compare_func | |
25 | }; | |
26 | ||
46e16b34 LP |
27 | |
28 | void path_hash_func(const void *p, struct siphash *state) { | |
29 | const char *q = p; | |
30 | size_t n; | |
31 | ||
32 | assert(q); | |
33 | assert(state); | |
34 | ||
35 | /* Calculates a hash for a path in a way this duplicate inner slashes don't make a differences, and also | |
36 | * whether there's a trailing slash or not. This fits well with the semantics of path_compare(), which does | |
37 | * similar checks and also doesn't care for trailing slashes. Note that relative and absolute paths (i.e. those | |
38 | * which begin in a slash or not) will hash differently though. */ | |
39 | ||
40 | n = strspn(q, "/"); | |
41 | if (n > 0) { /* Eat up initial slashes, and add one "/" to the hash for all of them */ | |
42 | siphash24_compress(q, 1, state); | |
43 | q += n; | |
44 | } | |
45 | ||
46 | for (;;) { | |
47 | /* Determine length of next component */ | |
48 | n = strcspn(q, "/"); | |
49 | if (n == 0) /* Reached the end? */ | |
50 | break; | |
51 | ||
52 | /* Add this component to the hash and skip over it */ | |
53 | siphash24_compress(q, n, state); | |
54 | q += n; | |
55 | ||
56 | /* How many slashes follow this component? */ | |
57 | n = strspn(q, "/"); | |
58 | if (q[n] == 0) /* Is this a trailing slash? If so, we are at the end, and don't care about the slashes anymore */ | |
59 | break; | |
60 | ||
61 | /* We are not add the end yet. Hash exactly one slash for all of the ones we just encountered. */ | |
62 | siphash24_compress(q, 1, state); | |
63 | q += n; | |
64 | } | |
65 | } | |
66 | ||
67 | int path_compare_func(const void *a, const void *b) { | |
68 | return path_compare(a, b); | |
69 | } | |
70 | ||
71 | const struct hash_ops path_hash_ops = { | |
72 | .hash = path_hash_func, | |
73 | .compare = path_compare_func | |
74 | }; | |
75 | ||
758dd67e LP |
76 | void trivial_hash_func(const void *p, struct siphash *state) { |
77 | siphash24_compress(&p, sizeof(p), state); | |
78 | } | |
79 | ||
80 | int trivial_compare_func(const void *a, const void *b) { | |
81 | return a < b ? -1 : (a > b ? 1 : 0); | |
82 | } | |
83 | ||
84 | const struct hash_ops trivial_hash_ops = { | |
85 | .hash = trivial_hash_func, | |
86 | .compare = trivial_compare_func | |
87 | }; | |
88 | ||
89 | void uint64_hash_func(const void *p, struct siphash *state) { | |
90 | siphash24_compress(p, sizeof(uint64_t), state); | |
91 | } | |
92 | ||
93 | int uint64_compare_func(const void *_a, const void *_b) { | |
94 | uint64_t a, b; | |
95 | a = *(const uint64_t*) _a; | |
96 | b = *(const uint64_t*) _b; | |
97 | return a < b ? -1 : (a > b ? 1 : 0); | |
98 | } | |
99 | ||
100 | const struct hash_ops uint64_hash_ops = { | |
101 | .hash = uint64_hash_func, | |
102 | .compare = uint64_compare_func | |
103 | }; | |
104 | ||
105 | #if SIZEOF_DEV_T != 8 | |
106 | void devt_hash_func(const void *p, struct siphash *state) { | |
107 | siphash24_compress(p, sizeof(dev_t), state); | |
108 | } | |
109 | ||
110 | int devt_compare_func(const void *_a, const void *_b) { | |
111 | dev_t a, b; | |
112 | a = *(const dev_t*) _a; | |
113 | b = *(const dev_t*) _b; | |
114 | return a < b ? -1 : (a > b ? 1 : 0); | |
115 | } | |
116 | ||
117 | const struct hash_ops devt_hash_ops = { | |
118 | .hash = devt_hash_func, | |
119 | .compare = devt_compare_func | |
120 | }; | |
121 | #endif |